| Optimization of a Hierarchical Porous-Structured Reactor to Mitigate Mass Transport Limitations for Efficient Electrocatalytic Ammonia Oxidation through a Three-Electron-Transfer Pathway | |
Liu, Zichen ; Zhang, Gong; Lan, Huachun; Liu, Huijuan; Qu, Jiuhui
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| 2021-09-21 | |
| Source Publication | ENVIRONMENTAL SCIENCE & TECHNOLOGY
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| ISSN | 0013-936X |
| Volume | 55Issue:18Pages:12596-12606 |
| Abstract | Regulation of fast three-electron-transfer processes for electrocatalytic oxidation of ammonia to nitrogen by achieving efficient generation and utilization of active sites is the optimal strategy in ammonia-containing wastewater treatment. However, the limited number of accessible active sites and sluggish interfacial mass transfer are two main bottlenecks restricting conventional ammonia oxidation configurations. Herein, we develop a macroporous Ni foam electrode integrated with vertically aligned two-dimensional mesoporous Ni2P nanosheets to create sufficient exposure of active centers. A novel ammonia oxidation reactor with the developed hierarchical porous-structured electrodes was assembled to construct an intensified microfluidic process with flow-through operation to mitigate macroscopic mass transport limitations. The confined microreaction space in the hierarchical porous reactor further promotes spontaneous nanoscale diffusion/convection of the target contaminant to high-valence Ni sites and enhances the microscopic mass transfer. The combined results of electrochemical measurements and in situ Raman spectra showed that the ammonia degradation mechanism results from direct oxidation by the high-valence Ni, significantly different from the conventional indirect active-chlorine-species-mediated oxidation. The optimized reactor achieves high-efficiency three-electron-transfer ammonia conversion with an ammonia removal efficiency of similar to 70% from an initial concentration of similar to 1400 mg/L and byproduct production of similar to 4%, significantly superior to a conversion unit comprising a featureless Ni-based electrode in the immersed configuration, which had >50% byproduct yield. 20 days of continuous operation under variable conditions achieved >90% ammonia degradation performance and an energy consumption of 25.42 kW h kg(-1) N (1 order of magnitude lower than the active-chlorine-mediated process), showing the potential of the reactor in medium-concentration ammonia-containing wastewater treatment. |
| Department | 环境水质学国家重点实验室 |
| Keyword | hierarchical porous structure mass transport intensification electrocatalytic ammonia oxidation three-electron-transfer transition-metal phosphide |
| WOS Research Area | Engineering, Environmental ; Environmental Sciences |
| Document Type | 期刊论文 |
| Identifier | https://ir.rcees.ac.cn/handle/311016/45971 |
| Collection | 环境水质学国家重点实验室 |
| Affiliation | 1.Chinese Acad Sci, Res Ctr Ecoenvironm Sci, State Key Lab Environm Aquat Chem, Beijing 100085, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Tsinghua Univ, Ctr Water & Ecol, Sch Environm, State Key Joint Lab Environm Simulat & Pollut Con, Beijing 100084, Peoples R China 4.Chinese Acad Sci, Res Ctr Ecoenvironm Sci, Key Lab Drinking Water Sci & Technol, Beijing 100085, Peoples R China |
| Recommended Citation GB/T 7714 | Liu, Zichen,Zhang, Gong,Lan, Huachun,et al. Optimization of a Hierarchical Porous-Structured Reactor to Mitigate Mass Transport Limitations for Efficient Electrocatalytic Ammonia Oxidation through a Three-Electron-Transfer Pathway[J]. ENVIRONMENTAL SCIENCE & TECHNOLOGY,2021,55(18):12596-12606. |
| APA | Liu, Zichen,Zhang, Gong,Lan, Huachun,Liu, Huijuan,&Qu, Jiuhui.(2021).Optimization of a Hierarchical Porous-Structured Reactor to Mitigate Mass Transport Limitations for Efficient Electrocatalytic Ammonia Oxidation through a Three-Electron-Transfer Pathway.ENVIRONMENTAL SCIENCE & TECHNOLOGY,55(18),12596-12606. |
| MLA | Liu, Zichen,et al."Optimization of a Hierarchical Porous-Structured Reactor to Mitigate Mass Transport Limitations for Efficient Electrocatalytic Ammonia Oxidation through a Three-Electron-Transfer Pathway".ENVIRONMENTAL SCIENCE & TECHNOLOGY 55.18(2021):12596-12606. |
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